Locking means for centrifugal molds



Nov. 27, 1956 A, B, HEMSTREET 2,771,647

LOCKING MEANS FOR CNTRIF'UGAL MOLDS 2 Sheets-Sheet l Filed June 9. 1955 um wm.\\\ NN @N @N mm. MvN Nm um. Umd WN .v .slllll a@ NN ON S NN NN MVN nu@ m@ ma d @www e. H M we@ M a w bm Nm. NN Nm. k .WM i WMM Gm. \\W.\ V

Nov. 27, 1956 A. B. HEMsTRr-:l-:T 2,771,647

LOCK'ING MEANS FOR CENTRIF'UGAL MOLDS 2 Sheets-Sheet 2 Filed June 9'. 1953 LOCKING NEANS FR CENTRIFUGAL MOLDS Albert B. Hemstreet, East Haddam, Conn.

Application .lune 9, 1953, Serial No. 360,547

11 Claims. (Cl. 22-113.5)

The present invention relates to improvements in molds of the type used in centrifugal casting machines and particularly to means for locking the several parts of a mold together during the casting operation.

More particularly still the invention relates to improvements in molds of the type disclosed in my Patent No. 2,506,216, issued May 2, 1950. In that patent there was disclosed a self-locking means for centrifugal molds in which balls placed in radial bores in one portion of a mold moved outwardly under centrifugal force and into an interior annular groove of another part of the mold thereby holding the parts together. The mold of that patent was intended for use with a casting machine having a vertical spindle and the locking means was entirely satisfactory for this use. However, when an attempt is made to `use the same locking means in connection with molds mounted on a horizontal spindle the operation is less satisfactory, and the present invention resulted from this situation.

In accordance with the present invention the mold parts are locked together due to inertia and thus as the machine starts locking takes place. Additionally, centrifugal force retains the mold locked even though the inertia means should become inoperative. The inertia locking means of the present invention is furthermore so constructed that the mold parts may be manually locked together prior to initiation of the rotation of the mold.

It is an object of the invention to provide means for locking the several parts of a centrifugal casting mold together both prior to and during the casting operation.

It is another object of the invention to provide inertia operated means for effecting the mentioned locking.

It is still another object of the invention to provide manual means to initiate the mold locking operation when this is desirable.

Other objects and features of the invention will be apparent when the following description is considered in connection with the annexed drawings, in which,

Figure l is a transverse cross-sectional view of a typical centrifugal casting mold having the locking means of my invention embodied therein;

Figure 2 is an end elevation of the mold of Figure 1;

Figure 3 is a transverse cross-sectional View of the same mold as shown in Figures 1 and 2 embodying a modified form of locking means;

Figure 4 is an end elevation of the mold of Figure 3;

Figure 5 shows a second modification of the locking means embodied in the same typical mold as seen in the preceding figures; and

Figure 6 is an end elevation, with a portion broken away, of the mold of Figure 5.

Referring now to the drawings, there is shown at 10 a tapered spindle which is adapted to be received in a chuck or tapered spindle seat in the rotatable spindle of a centrifugal molding machine. Secured to the spindle 10 in any suitable manner or formed as an integral part thereof is a disk 11 which disk is provided with an annular recess 12 on its left hand face, the recess being formed 2,771,647 Patented Nov. 27, 1956 by the peripheral ange 13. Evenly spaced about the periphery of disk 11 are radial bores 14 in each of which a steel ball 15 is placed being held by a swaged over rim as shown. The right hand end of the disk 11 is turned down as indicated at 16 and is provided with a thread 17. A handwheel 18 provided with mating interior threads is threaded onto the portion 17, the handwheel having an annular rim 2t), the tapered outer edge 27 of which bears against the balls 15.

Two pins 22 and 23, one, 22, fixed in the disk 11 and the other, 23, fixed in a handwheel 18 limit the amount of rotation of the handwheel relative to disk 11 to slightly less than one complete turn.

In the recess on the end of the disk or plate 11 there may be placed a lining 24 of refractory low heat conductive material such for example as carbon. particular typical mold shown there is also a recess in the end of the disk or plate 11 in which a centering stub 25 may be placed.

The cover for the mold thus far described comprises two cylindrical sections 26 and 27 which are threadedly interconnected as shown. Portion 26 is in the form of an open-ended ring while portion 27 is in the form of a cap having an end wall. Mounted in the cap 27 is a lining 28 which may be of refractory low heat conductive material Such as carbon and which comprises a separate unit having a central aperture boss 30 which extends a short distance through an opening in the end wall of the cap 27. The inner wall of the ring 26 adjacent its right hand edge is provided with an annular groove 31 which when the mold is assembled as shown is radially aligned with the balls 15.

As will be obvious, when the handwheel 18 is rotated in one direction the tapered portion 20 thereof will force the balls 15 outwardly into the annular groove 31 of member 26, thus locking the cylindrical portion 26 to the disk or plate 11. The handwheel 18 is preferably made relatively heavy so that as the shaft 10 is accelerated rapidly the inertia of the member 18 causes it to rotate relative to the shaft and to thedisk 11 to thereby lock the mold portion 26 to the disk 11. However, if desir able the handwheel 18 may be rotated by hand prior to the rotation of shaft 10 thereby causing the mold parts to be locked together before any rotation occurs.

It will be noted that once the spindle 10 and mold have come up to speed the balls 15 are forced outwardly by centrifugal force and lock the mold parts 11 and 26 together irrespective of the positioning of the handwheel 18. Thus the mold is self-locking in the same manner as the mold described in my prior patent above-mentioned but in addition may be locked as the result of inertia prior to the spindle attaining its full speed and may even be manually locked before rotation starts.

Referring now to Figures 3 and 4, it will be seen that the embodiment of the invention shown therein is in general identical with that of Figures 2 and 3. In this embodiment, however, the flange 20 of the handwheel 18 is replaced by a number of steelballs 32 equal in number to the balls 15 and placed in bores 33 in the disk 11 extending at right angles to the bores 14. Here again the rotation of the portion 18 is limited as respects the mating threaded portion 16. In this instance the limitation is effected by means of a pin 34 xed in the disk 11 and extending toward the right into a groove 35 in the left hand face of member 18, this pin cooperating with a pin 36 in a radial bore 37 in the handwheel 18 to limit the rotation of that handwheel with respect to the spindle 10 and disk 11.

As in the rst form of the invention discussed, rotation of the handwheel 18 will cause the balls 15 to move outwardly into the annular groove 31 in mold part 26 and lock that part to the disk or plate 11. Likewise, as in In the` 3 the rst form, centrifugal force will cause the balls 15 to move outwardly even when they have not beenl moved outwardly by means of manual or inertia rotation of the handwheel 18, thus assuring that the parts will be held intheir locked condition during the casting operation.

Referring now to Figure 5 there is shown therein a third form of the invention in which the handwheel 18 is loosely mounted on the turned-down portion 16 on disk 12 instead of being threaded thereon and is held in position by means of the spring washer 40 placed in the annular groove 41. In this instance the balls 15 are forced outwardly by means of a camming surface formed on the outer edge of the inwardly extending flange 42. of the handwheel 13, the camming surface being best shown at 43 in- Figure 6. As will be obvious when the handwheel 18 is rotated the camming surface forces the balls 15 outwardly and into the end of a groove 31 in the mold member 26 locking that member to the disk 11 in the same general manner' as has been heretofore described. As in the forms previously described, the handwheel 18 may be either manually or inertia operated and, as in the forms previously described, the balls 15 will move outwardly under centrifugal force and cause the mold parts to be locked together when the spindle 10 is up to speed even though the handwheel 18 has not been operated.

While I have described preferred embodiments of my invention it will be understood that numerous other modiiications may be made Without departing from the spirit of the invention. I wish, therefore, to be limited not by the foregoing description which is given for purposes of illustration only, but on the contrary to be limited only by the claims granted to me.

What is claimed is:

l. In a centrifugal mold of the type described, in combination, a pair of substantially cylindrical telescoping parts forming a molding cavity when assembled, each of said parts having at least one recess in the overlapping area of the parts, a ball held in the recess of one part and radially movable under centrifugal force to project partially into the recess of the other part to lock the parts together, and means mounted on said one part and having limited rotation with respect thereto to project said ball into the recess of said other part at one extreme of the rotary movement of said means.

2. A device as claimed in claim 1, characterized in that the recess in said other part comprises an internal annular groove.

3. A device as claimed in claim 2 characterized in that said ball projecting means comprises a member projecting into said recess of said one mold part radially inwardly of said ball.

4. A device as claimed in claim 3, characterized in that said member extends axially of said one mold part.

5. In a centrifugal mold of the type described, in combination, a pair of substantially cylindrical telescoping parts forming a molding cavity when assembled, each of said parts having at least one radial recess in the overlapping area of the parts, a ball held in said recess of said one mold part aud radially movable to project partially into the recess of the other part, a handwheel threadedly mounted on said one mold part, an axially extending annular groove in said one mold part, said groove communieating with the said recess, a flange formed ou said handwheel and extending through said groove into said recess and a cam surface formed on said flange, said cam surface cooperating with said ball to project it into the recess of said other mold part when said handwheel is rotated to the limit of its movement in one direction.

6. A device as claimed in claim 5, characterized in that said handwheel is made relatively heavy and is operable by inertia upon rapid acceleration of the mold.

7. A device as claimed in claim 5, characterized in that said one mold part and said handwheel are provided with pins extending in opposite directions and on the same circumference, said pins serving to limit the rotational movement of said` handwheel on said one mold part.

8. In a centrifugal mold of the type described, in combination, a pair of substantially cylindrical telescoping parts forming a molding cavity when assembled, each of said parts having at least one radial recess in the overlapping area of the parts, a ball held in said recess of said one mold part and radially movable to project partially into the recess of the other part, a handwheel threadedly mounted on said one mold part, an axially extending bore communicating with` said recess inl said one mold part, and a ball mounted in said axial bore and bearing against said first-mentioned ball and said handwheel, whereby rotation of said handwheel upon said one mold part causes said handwheel to move axially, bearing against said second' ball and forcing said first ball into the recess of said other mold part.

9. A device as claimed in claim 8, characterized in that said one mold part and said handwheel have pins therein, one of' said pins extending into the rotary path of the other whereby the rotary movement of said handwheel with respect to said one mold part is limited.

l0. In a centrifugal mold of the type described, in combination, a pair of substantially cylindrical telescoping parts forming a molding cavity when assembled, each of said parts having at least one radial recess in the overlapping area of the parts, a ball held in said recess of said one mold part and radially movable to project partially into the recess of the other part, a handwheel rotatably mounted on said one mold part, an axially extending annular groove communicatingwith said recess, an axially extending ilange on said handwheel, said flange extending into said annular groove and lying radially inwardly of said ball, and a camming surface formed on said flange to project said ball into the recess of said other mold part-upon movement of said handwheel to one limit of its rotational movement.

l1. A device as claimed in claim l0, characterized in that said camming surface cooperates with said ball to form a stop to the rotational movement of said handwheel in either direction.

References Cited in the le of this patent UNITED STATES PATENTS 2,290,215 Stenberg Julyl 21, 1942 2,506,216 Hemstreet May 2, 1950 2,601,389 Guelf June 24, 1952 FORETGN PATENTS 646,542 Great Britain Nov. 22, 1950 

